Cooling system of internal combustion engines



K. KATO May 25, 193 7.

COOLING SYSTEM OF INTERNAL COMBUSTION ENGINES Filed July 3, 1935 9 2 $7H m u 6 a x 0 r MW 7 J S w 0 a 2 A M 7 Nil 0 0 F\ 0 Fly. 2

Patented May 25, 1937 A T E T GFHQE COOLING SYSTEM OF INTERNAL COMBUS-TION ENGINES Kihachi Kate, Hongo-ku, Tokyo, Japan, as-

signor to Minato Tsuji, Tokyo, Japan Application July 3, 1935, SerialNo. 29,750

In Japan 4 Claims.

This invention relates to the cooling system for an internal combustionengine cylinder, and more particularly to that type in which the enginecylinder is cooled by the air directly applied to the outside surface ofthe cylinder.

It is an object of the present invention to provide a novel coolingsystem which is reliable and efiicient in operation and particularlyadapted to insure suitable cooling under adverse conditions.

It is another object of the invention to provide a system which usesexhaust gas and compressed air which are conducted to the cylinderjacket for forced draft cooling and the air contacting with finsextending beyond the outside surface of the cylinder jacket for naturaldraft cooling,

It is a further object of the invention to provide such a deviceembodying a mufiier which cools, and also silences the exhaust gas andallows it to expand.

The water jacketing system of cooling internal combustion engines is inmany respects unsatisfactory and the air cooling system is to bepreferred. There are however difficulties in the way of providing asatisfactory air cooling system.

A forced draft system requires power to drive the impeller of the blowerto feed the cooling air and is moreover apt to reduce the temperature totoo great an extent in winter. A natural draft system is foundinadequate in that the cylinder is not sufficiently cooled.

Applicants invention combines these two air cooling systems in a way tosecure the advantages of both and eliminate their defects.

According to this invention the exhaust gases are cooled in the exhaustpipe and are used to cool the cylinder, a stream of compressedatmospheric air entering the exhaust pipe and assisting in said coolingof the engine.

By the combined system of natural and forced draft, the engine can beadequately cooled, avoiding overheating and overcooling,

because as the load of the engine increases more exhaust gas will bedelivered, and as the load of the engine decreases less exhaust gas willbe delivered.

The invention may be carried into practice in various ways but oneembodiment will be described by way of example with reference to the.

accompanying drawing, in which Fig. 1 is a somewhat diagrammatic sideelevation partly in section of an internal combustion engine.

Fig. 2 is a plan View of Fig. 1; Fig. 3 is a lateral July 9, 1934section of one cylinder; Fig. 4 is a plan view of one cylinder, thecylinder head being removed.

Referring to Fig. 1 of the drawing, there is shown the cylinders ofinternal combustion engine l which are cooled by air passing through thejacketed space or other conduits fixed to the cylinders. The exhaustmanifold 2 leads to the cooling mufiler 5 in which is inserted a centralrod 3 surrounded by spiral plate 4 which is corrugated in th centralportion and smooth on the outer portion and more particularly the endwhich is nearer to the exhaust manifold may be made acute for thepurpose of reducing the back pressure of the exhaust gas. Any number ofsuch plates in series may be used but in the drawing two are shown.

By means of such a muffler, the exhaust gas noise is reduced and theexhaust gas expands freely during its revolving motion and itstemperature is reduced to such an extent that the expanded gas can beused for the purpose of cooling the engine cylinders effectively andreliably.

The cooled gas is then conducted to the cooling manifold l8 and thencylinder head 1. The mixing device 6 is interposed between the mufflerand cooling gas manifold IS. The air is compressed by the impeller 9which is driven by step up gearing 88, the gear 8 is fixed to crankshaft of the engine and the gear 8 is fixed to the impeller shaft 9. Thecompressed air is conducted by pipe l0 which has the valve 20 operatedby the controlling rod I9. The mixing device comprises a jet I l and ofVenturi type construction 12. The gas mixed with the air is conducted tothe cooling manifold l8 and is then directed about the cylinder head 1'.The cylinder jacket has ribs I 4 as shown in Fig. 4 and forms manyconduits l3 for the cooling gas. The. ribs l5 outside of jacket I can beprovided to assist the cooling. After cooling the cylinders, the gascollects in the space l6 and finally escapes through the exhaust pipell.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. In an internal combustion engine, a cylinder, a cooling jacketsurrounding said cylinder, an exhaust conduit leading from said cylinderto said cooling jacket, means in said conduit for cooling the exhaustgases, an air compressor and an air conduit from said air compressorleading into said exhaust conduit at a point between said cooling meansand said cooling jacket and an outlet from said cooling jacket.

2. The device as claimed in claim 1, wherein at said constructionopening toward the cooling jacket.

4. In an internal combustion engine, a cylinder, a cooling jacketsurrounding said cylinder, an exhaust conduit leading from said cylinderand to said cooling jacket, means connected with said exhaust conduitfor cooling the exhaust gases and means for admitting air into saidexhaust conduit to mix with the exhaust gases, and means for compressingthe air, the means for admitting said air to the exhaust conduit beingso arranged as to add to the velocity of the exhaust gases.

KIHACHI KATO.

